1. Technical Field
The present invention relates to an electrophoresis dispersion liquid, and electrophoresis sheet, and electrophoresis device, and electronic apparatus.
2. Related Art
Generally, it is known that when a dispersion system in which fine particles are dispersed in a liquid is acted on by an electrical field, the fine particles are moved (migrate) in the liquid due to Coulomb force. This phenomenon is known as electrophoresis, and in recent years, electrophoresis display devices in which desired information (images) is displayed using electrophoresis have garnered attention as new display devices.
The electrophoresis display device has display memory properties in a state in which application of a voltage is stopped and wide viewing angle properties, and is capable of high contrast display with low power consumption.
Since electrophoresis display devices are non-light emitting display devices, electrophoresis display devices are better for the eyes compared to a light-emitting display device such as a cathode ray tube.
Such an electrophoresis display device provided with a dispersion in which the electrophoretic particles are dispersed in a solvent as an electrophoresis dispersion liquid arranged between a pair of substrates having electrodes is known.
In the electrophoresis dispersion liquid of this configuration, electrophoretic particles including particles with positive chargeability and particles with negative chargeability are used, and, in so doing, it is possible for desired information (image) to be displayed by applying a voltage between the pair of substrates (electrodes).
In the electrophoresis dispersion liquid including the positively charged and negatively charged electrophoretic particles, a method in which positive or negative chargeability is expressed by the electrophoretic particles is generally achieved by introducing an ion-derived substituent (ionic group) into the particles (for example, refer to JP-A-5-173193).
However, in the electrophoresis dispersion liquid with such a configuration, exchanging ion types in the electrophoresis dispersion liquid becomes complicated due to the addition of a dispersant in the electrophoresis dispersion liquid. Therefore, a problem arises where the charging state of the electrophoretic particles varies greatly and, as a result, the display characteristics of the electrophoresis display device become unstable due to the dispersion and aggregation state of the electrophoretic particles and temperature changes in the electrophoresis dispersion liquid.